cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ptrace.c (4721B)

      1/*
      2 * `ptrace' system call
      3 *
      4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
      5 * Copyright (C) 2007-2009 PetaLogix
      6 * Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com>
      7 *
      8 * derived from arch/v850/kernel/ptrace.c
      9 *
     10 * Copyright (C) 2002,03 NEC Electronics Corporation
     11 * Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
     12 *
     13 * Derived from arch/mips/kernel/ptrace.c:
     14 *
     15 * Copyright (C) 1992 Ross Biro
     16 * Copyright (C) Linus Torvalds
     17 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
     18 * Copyright (C) 1996 David S. Miller
     19 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
     20 * Copyright (C) 1999 MIPS Technologies, Inc.
     21 *
     22 * This file is subject to the terms and conditions of the GNU General
     23 * Public License. See the file COPYING in the main directory of this
     24 * archive for more details.
     25 */
     26
     27#include <linux/kernel.h>
     28#include <linux/mm.h>
     29#include <linux/sched.h>
     30#include <linux/sched/task_stack.h>
     31#include <linux/ptrace.h>
     32#include <linux/signal.h>
     33#include <linux/elf.h>
     34#include <linux/audit.h>
     35#include <linux/seccomp.h>
     36
     37#include <linux/errno.h>
     38#include <asm/processor.h>
     39#include <linux/uaccess.h>
     40#include <asm/asm-offsets.h>
     41#include <asm/cacheflush.h>
     42#include <asm/syscall.h>
     43#include <linux/io.h>
     44
     45/* Returns the address where the register at REG_OFFS in P is stashed away. */
     46static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
     47					struct task_struct *t)
     48{
     49	struct pt_regs *regs;
     50
     51	/*
     52	 * Three basic cases:
     53	 *
     54	 * (1)	A register normally saved before calling the scheduler, is
     55	 *	available in the kernel entry pt_regs structure at the top
     56	 *	of the kernel stack. The kernel trap/irq exit path takes
     57	 *	care to save/restore almost all registers for ptrace'd
     58	 *	processes.
     59	 *
     60	 * (2)	A call-clobbered register, where the process P entered the
     61	 *	kernel via [syscall] trap, is not stored anywhere; that's
     62	 *	OK, because such registers are not expected to be preserved
     63	 *	when the trap returns anyway (so we don't actually bother to
     64	 *	test for this case).
     65	 *
     66	 * (3)	A few registers not used at all by the kernel, and so
     67	 *	normally never saved except by context-switches, are in the
     68	 *	context switch state.
     69	 */
     70
     71	/* Register saved during kernel entry (or not available). */
     72	regs = task_pt_regs(t);
     73
     74	return (microblaze_reg_t *)((char *)regs + reg_offs);
     75}
     76
     77long arch_ptrace(struct task_struct *child, long request,
     78		 unsigned long addr, unsigned long data)
     79{
     80	int rval;
     81	unsigned long val = 0;
     82
     83	switch (request) {
     84	/* Read/write the word at location ADDR in the registers. */
     85	case PTRACE_PEEKUSR:
     86	case PTRACE_POKEUSR:
     87		pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
     88		rval = 0;
     89		if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
     90			/*
     91			 * Special requests that don't actually correspond
     92			 * to offsets in struct pt_regs.
     93			 */
     94			if (addr == PT_TEXT_ADDR) {
     95				val = child->mm->start_code;
     96			} else if (addr == PT_DATA_ADDR) {
     97				val = child->mm->start_data;
     98			} else if (addr == PT_TEXT_LEN) {
     99				val = child->mm->end_code
    100					- child->mm->start_code;
    101			} else {
    102				rval = -EIO;
    103			}
    104		} else if (addr < PT_SIZE && (addr & 0x3) == 0) {
    105			microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
    106			if (request == PTRACE_PEEKUSR)
    107				val = *reg_addr;
    108			else {
    109#if 1
    110				*reg_addr = data;
    111#else
    112				/* MS potential problem on WB system
    113				 * Be aware that reg_addr is virtual address
    114				 * virt_to_phys conversion is necessary.
    115				 * This could be sensible solution.
    116				 */
    117				u32 paddr = virt_to_phys((u32)reg_addr);
    118				invalidate_icache_range(paddr, paddr + 4);
    119				*reg_addr = data;
    120				flush_dcache_range(paddr, paddr + 4);
    121#endif
    122			}
    123		} else
    124			rval = -EIO;
    125
    126		if (rval == 0 && request == PTRACE_PEEKUSR)
    127			rval = put_user(val, (unsigned long __user *)data);
    128		break;
    129	default:
    130		rval = ptrace_request(child, request, addr, data);
    131	}
    132	return rval;
    133}
    134
    135asmlinkage unsigned long do_syscall_trace_enter(struct pt_regs *regs)
    136{
    137	unsigned long ret = 0;
    138
    139	secure_computing_strict(regs->r12);
    140
    141	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
    142	    ptrace_report_syscall_entry(regs))
    143		/*
    144		 * Tracing decided this syscall should not happen.
    145		 * We'll return a bogus call number to get an ENOSYS
    146		 * error, but leave the original number in regs->regs[0].
    147		 */
    148		ret = -1L;
    149
    150	audit_syscall_entry(regs->r12, regs->r5, regs->r6, regs->r7, regs->r8);
    151
    152	return ret ?: regs->r12;
    153}
    154
    155asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
    156{
    157	int step;
    158
    159	audit_syscall_exit(regs);
    160
    161	step = test_thread_flag(TIF_SINGLESTEP);
    162	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
    163		ptrace_report_syscall_exit(regs, step);
    164}
    165
    166void ptrace_disable(struct task_struct *child)
    167{
    168	/* nothing to do */
    169}